Triphenylphosphine-Mediated Synthesis of Methyl 2-Aroyloxypropenoates from 2-Aroyl-2-methoxycarbonyloxiranes
摘要:
A new synthesis of several 2-aroyloxypropenoic acid methyl esters 5 by the reaction of 2-aroyl-2-methoxycarbonyloxiranes 2 with triphenylphosphine in tetrahydrofuran has been described.
One-Pot Preparation of 1-Acyl-1-methoxycarbonyloxiranes and 1-Acyl-1-cyanooxiranes from Methyl 3-Hydroxy-2-methylenealkanoates or 3-Aryl-3-hydroxy-2-methylenepropanenitriles
Treatment of Baylis–Hillman adducts with iodosobenzene (PhIO) in the presence of a catalytic amount of KBr in water at room temperature afforded the corresponding acyloxiranes in good yields.
IBX/LiBr-promoted one-pot oxidative anti-Markownikov bromohydroxylation/bromoalkoxylation of Baylis–Hillman olefins
作者:Lal Dhar S. Yadav、Chhama Awasthi
DOI:10.1016/j.tetlet.2008.11.119
日期:2009.2
The first example of one-pot oxidative anti-Markownikov bromohydroxylation and bromoalkoxylation of Baylis-Hillman (BH) adducts (olefins) is reported. The reaction is performed at rt using LiBr as the bromine source and 2-iodoxybenzoic acid (IBX) as the oxidant. The process involves oxidation of BH adducts with IBX to give beta-ketomethylene compounds in situ, which undergo highly regioselective vicinal functionalization with LiBr/H2O or LiBr/ROH in the same vessel to afford of alpha-bromo-beta-hydroxy or alpha-bromo-beta-alkoxy compounds, respectively, in excellent yields. The alpha-bromo-beta-hydroxy Compounds are readily transformed into epoxides in aq NaOH. (C) 2008 Elsevier Ltd. All rights reserved.
FOUCAUD, ANDRE;LE, ROUILLE ELIANE, SYNTHESIS (BRD),(1990) N, C. 787-789